1. Field of the Invention
The present invention relates to managing services provided by a telecommunication network. To be more precise, it relates to supervising the quality of services provided by a telecommunication network.
2. Description of the Prior Art
The services concerned can be multimedia transmission services on data networks, usually called “voice over Internet Protocol” or “voice over IP” services, enabling transmission of video, sound, etc., multiconference services, etc.
These services, and those yet to be introduced, necessitate high qualities of service. There are different quality criteria, the importance of which varies as a function of the type of service: bit rate, packet loss, jitter between packets, etc.
The quality criteria can be covered by an agreement between the operator of a telecommunication network and its clients (for example service providers). This agreement is usually called the service level agreement (SLA).
A fault affecting a network element, congestion on a link between network nodes or within a network node, etc. can impact on the quality of one or more services.
A reduction in the quality of service can have a strong commercial impact in that it can impact on client satisfaction or even contravene the SLA that has been negotiated.
It is therefore important for an operator to have available a system for managing services that is capable of determining the cause of the reduced quality of service as soon as possible. This enables the operator (or the service management system itself) to react as soon as possible, by reconfiguring the telecommunication network, repairing the faulty network element, or bringing into operation clauses of the agreement negotiated with the client (billed service reduction, for example), etc.
Prior art solutions are based on collecting alarms from the network. A network element fault, congestion, etc. must generate a stream of alarms from the network elements concerned to a network management system. The network elements can be of diverse kinds. In particular, they can be network nodes (switches, routers, etc.) or links between network nodes.
The network management and service management systems cooperate.
A correlation is then established to sort the stream of alarms and deduce from it the cause of the reduction in the quality of service.
However, there is an excessive number of alarms to be processed. The processing time is then too long for the service management system to  react within an acceptable time. During the processing time the reduction in quality may worsen to the point of violating the limits imposed by the SLA.
The object of the present invention is to propose a more effective solution to the problem of detecting the causes of a reduction in the quality of service.